塔中I号气田超深水平井储层改造工艺技术研究与应用

RESEARCH AND APPLICATION OF STIMULATION TECHNOLOGY OF ULTRA- DEEP HORIZONTAL WELL IN TAZHONG NO.1 GAS FIELD

塔里木盆地塔中I号气田中古8-中古43井区主力开发层系为奥陶系鹰山组碳酸盐岩。储层垂深6 000 m左右,水平井段一般超过1 000 m,水平井斜深7 000 m以上。储层基质的物性总体较差,孔洞发育,属于非均质性较强的缝洞型储层。前期酸压井改造效果受地质因素影响较大,水平井改造有效率偏低。同时,由于大多数井在生产后期存在出水或者产量快速下降的情况,需要进行找堵水或者重复改造作业,因此要求第一次改造后井筒全通径。通过对前期酸压井的后评估分析,结合工作液体系研究、超深水平井分段改造工艺优选及施工参数优化,形成了以裸眼封隔器+压控式筛管配合黄原胶、自生酸的超深水平井储层改造系列技术。在满足超深水平井分段改造需求的同时,实现了改造后井筒全通径,便于后期重复改造及修井作业。2013年至今共进行了29口水平井的现场应用,其中26口井获工业油气流,施工成功率100%,有效率90%。平均单井压后油气当量从前期的27.7 t/d提高到113.7 t/d,提产效果明显。该技术的成功应用,为塔中水平井的高效开发提供了有力的技术支撑,具有推广价值。

The main development layer in Zhonggu 8- 43 well field of Tarim Tazhong No. 1 gas field is Ordovician carbonate rock formation. The vertical depth of reservoir is about6000 m. Horizontal section is more than 1000 m while the well depth exceeds 7000 m. The carbonate reservoir has the characteristics of poor physicals,developed cavern and strong anisotropism. The stimulation effects of earlier acid fracturing wells were poor which were influenced by geologic factors. Based on the analysis of earlier acid fracturing effects,and combining the research on treatment fluid system,optimizing staged fracturing technologies and operation parameters,a series of ultra- deep horizontal well stimulation technologies which included open-hole packer,pressure- controlling liner coordinate with xanthan gum and self- generating acid were developed. This stimulation technologies could fulfill both the requirements of multi- stage stimulation of ultra- deep horizontal well and keep the full gauge hole unobstructed to allow workover and re- fracturing. Since2013,this stimulation technologies have been applied in 29 wells,of which 26 wells obtained commercial oil and gas flow.The application success ratio was 100%,the effective ratio was90%. The effect of the increase production was obvious from the earlier 27. 7 tons per day to 113. 7 tons per day. The successful application of this technology provided a technical support for high efficient development of horizontal wells in Tazhong.